U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Brian Kirby (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 26 - 50 of 96

Emergent Magnetic State in (111)-Oriented Quasi-Two-Dimensional Spinel Oxides

December 11, 2019
Author(s)
Xiaoran Liu, Sobhit Singh, Brian Kirby, Zhicheng Zhong, Yanwei Cao, Banabir Pal, Mikhail Kareev, Srimanta Middey, John W. Freeland, Padraic Shafer, Elke Arenholz, David Vanderbilt, Jak Chakhalian
We report on the emergent magnetic state of (111)-oriented CoCr 2O 4 ultrathin films sandwiched by Al 2O 3 in the quantum confined geometry. At the two-dimensional crossover, polarized neutron reflectometry reveals an anomalous enhancement of the total

Spin Seebeck Imaging of Spin-Torque Switching in Antiferromagnetic Pt/NiO Heterostructures

October 22, 2019
Author(s)
Isaiah Gray, Takahiro Moriyama, Nikhil Sivadas, Gregory M. Stiehl, John T. Heron, Ryan F. Need, Brian Kirby, David H. Low, Katja Nowack, Darrell G. Schlom, Daniel C. Ralph, Teruo Ono, Gregory D. Fuchs
We demonstrate the spin Seebeck microscope as a sensitive method for imaging in-plane antiferromagnetic order in thin films. Recently, antidamping spin-orbit torques have been used to reorient Neel order in antiferromagnetic devices. Although the readout

Using Structural Phase Transitions to Enhance the Coercivity of Ferromagnetic Films

October 17, 2019
Author(s)
Ryan F Need, Josh Lauzier, Logan Sutton, Brian J Kirby, Jose de la Venta
Storing information in magnetic recording technologies requires careful optimization of the recording media's magnetic properties. For example, heat-assisted magnetic recording (HAMR) relies on a pre-recording heating step that momentarily lowers the

Ultrathin Interfacial Layer with Suppressed Room Temperature Magnetization in Magnesium Aluminum Ferrite Thin Films

September 24, 2019
Author(s)
Jacob J. Wisser, Satoru Emori, Lauren Riddiford, Aaron Altman, Peng Li, Krishnamurthy Mahalingam, Brittany T. Urwin, Brandon M. Howe, Michael R. Page, Alexander Grutter, Brian Kirby, Yuri Suzuki
Low-damping magnetic oxide thin films with small thicknesses are essential for efficient insulator spintronic devices, particularly those driven by spin torques effects. Here, we investigate depth-resolved compositional and magnetic properties of epitaxial

Effect of Oxygen Stoichiometry on the Magnetization Profiles and Negative Magnetization in LSMO Thin Films

September 14, 2019
Author(s)
Robbyn Trappen, Alexander Grutter, Chih-Yeh Huang, Aubrey Penn, Navid Mottaghi, Saeed Yousefi, Allison Haertter, Shalini Kumari, James LeBeau, Brian Kirby, Mikel B. Holcomb
The depth dependent magnetization in thin film oxygen stoichiometric and oxygen deficient La 0.7Sr 0.3MnO 3 is investigated by using polarized neutron reflectivity. The stoichiometric sample shows enhanced interfacial magnetization relative to the rest of

Nanoscale Ferroelastic Twins Formed in Strained LaCoO 3 Films

March 29, 2019
Author(s)
Er-Jia Guo, Ryan Desautels, David Keavney, Manuel A. Roldan, Brian Kirby, Dongkyu Lee, Zhaoliang Liao, Timothy Charlton, Andreas Herklotz, T. Zac Ward, Michael R. Fitzsimmons, Ho Nyung Lee
The formation of twinning domains has been established as a major mechanism to accommodate epitaxial strain in rhombohedral ferroelastic oxide thin films. The elastic energy can be released at the expense of high interfacial energy at the domain boundaries

Exploring Interfacial Exchange Coupling and Sublattice Effect in Heavy Metal/Ferrimagnetic Insulator Heterostructures using Hall Measurements, X-Ray Magnetic Circular Dichroism, and Neutron Reflectometry

March 4, 2019
Author(s)
Qiming Shao, Alexander Grutter, Yawen Liu, Guoqiang Yu, Chao-Yao Yang, Dustin A. Gilbert, Elke Arenholz, Padraic Shafer, Xiaoyu Chi, Chi Tang, Mohammed Aldosary, Aryan Navabi, Qing Lin He, Brian Kirby, Jing Shi, Kang L. Wang
Ferrimagnetic insulators (FMIs), such as rare-earth iron garnets, are of considerable interest for low-power spintronics due to low Gilbert damping and the absence of free charge carriers. FMIs are also promising candidate materials for high-frequency

Phonon Localization in Heat Conduction

December 21, 2018
Author(s)
M. N. Luckyanova, J. Mendoza, H. Lu, B. Song, S. Huang, J. Zhou, M. Li., Y. Dong, H. Zhou, J. Garlow, L. Wu, Brian Kirby, Alexander Grutter, Alex A. Puretzky, Y. Zhu, M. S. Dresselhaus, A. Gossard, G. Chen
We report localization-like behavior in phonon heat conduction observed both in measurement of the thermal conductivities of GaAs/AlAs superlattice (SL) thin films with interfacial disorder caused by ErAs nanodots randomly distributed at the interfaces

Pulsed Laser Deposition Films from a Ba 2 FeMoO 6 Target onto SrTiO 3 [001]: Chemical and Magnetic Inhomogeneity

October 22, 2018
Author(s)
Daniel M. Pajerowski, Lisa J. Krayer, Brian Kirby, Brian B. Maranville, Julie Borchers, Kyeong-Won Kim, David P. Norton
We have used a combination of x-ray diffraction, atomic force microscopy, x-ray and neutron reflectivity, and x-ray photoelectron spectroscopy to investigate inhomogeneities within pulsed laser deposition, Ba 2FeMoO 6 films on SrTiO 3[001]. These results

Long-Range Electric Field Control of Permalloy Layers in Strain-Coupled Composite Multiferroics

October 18, 2018
Author(s)
Michelle E. Jamer, Colin R. Rementer, Anthony Barra, Alexander Grutter, Kevin Fitzell, Daniel Gopman, Julie Borchers, Gregory P. Carman, Brian Kirby, Jane P. Chang
Artificial composite multiferroic materials can be created by interfacing magnetostrictive and piezoelectric materials, allowing for electric field control of magnetic properties. For multilayer device applications, addition of weakly magnetostrictive

Ionic Tuning of Cobaltites at the Nanoscale

October 3, 2018
Author(s)
Dustin Allen Gilbert, Alexander J Grutter, Peyton D. Murray, Rajesh V. Chopdekar, Alexander M. Kane, Aleksey L. Ionin, Michael S. Lee, Steven R. Spurgeon, Brian J Kirby, Brian B. Maranville, Alpha T. N'Diaye, Apurva Mehta, Elke Arenholz, Kai Liu, Yayoi Takamura, Julie A. Borchers

Strain-Induced Competition between Ferromagnetism and Emergent Antiferromagnetism in (Eu,Sr)MnO 3

September 4, 2018
Author(s)
Alexander J Grutter, Steven M. Disseler, E. J. Moon, Dustin Allen Gilbert, E. Arenholz, A. Suter, T. Prokscha, Z. Salman, Brian J Kirby, S. J. May
We demonstrate emergent antiferromagnetic interactions is strained thin films of the mixed valence manganite (Eu,SR)MnO 3. Although the composition studied, Eu 0.7Sr 0.3MnO 3, will nominally yield a ferromagnetic phase in bulk, we observe significant

Topological Transitions Induced by Antiferromagnetism in a Thin-Film Topological Insulator

August 29, 2018
Author(s)
Qing Lin He, Gen Yin, Luyan Yu, Alexander Grutter, Lei Pan, Chui-Zhen Chen, Xiaoyu Che, Guoqiang Yu, Bin Zhang, Qiming Shao, Alexander L. Stern, Brian Casas, Jing Xia, Xiaodong Han, Brian Kirby, Roger K. Lake, K. T. Law, Kang L. Wang
Ferromagnetism in topological insulators (TIs) opens a topologically non-trivial exchange band gap, providing an exciting platform for manipulating the topological order through external magnetic field. Here, we experimentally show that the surface of an

Nanoscale Magnetic Localization in Exchange Strength Modulated Ferromagnets

August 3, 2018
Author(s)
Brian J Kirby, L. Fallarino, P. Riego, Brian B. Maranville, Casey W. Miller, A. Berger
Compositional grading can be used to continuously vary the "local" Curie temperature across the thickness of a ferromagnetic alloy thin film, allowing for a continuously moveable vertical boundary between strongly and weakly magnetized regions. The utility

Highly Contrasting Static Charging and Bias Stress Effects in Pentacene Transistors with Polystyrene Heterostructures Incorporating Oxidizable N,N'-Bis(4-Methoxyphenyl)aniline Side Chains as Gate Dielectrics

August 1, 2018
Author(s)
Qingyang Zhang, Tejaswini S. Kale, Evan Plunkett, Wei Shi, Brian Kirby, Daniel H. Reich, Howard E. Katz
Charge trapping and storage in polymer dielectrics can be harnessed for the control of semiconductor device behavior, including organic transistors. For example, gate insulators chosen for organic transistors have an important effect on both bias stress

Exchange-Biasing Topological Charges by Antiferromagnetism

July 17, 2018
Author(s)
Qing Lin He, Gen Yin, Alexander Grutter, Lei Pan, Xiaoyu Che, Guoqiang Yu, Dustin A. Gilbert, Steven M. Disseler, Yizhou Liu, Padraic Shafer, Bin Zhang, Yingying Wu, Brian Kirby, Elke Arenholz, Roger K. Lake, Xiaodong Han, Kang L. Wang, Xiaodong Han, Kang L. Wang
'Geometric' or 'topological' Hall effect is induced by the emergent gauge field experienced by the carriers adiabatically passing through chiral spin textures. This effect is an indication of non-trivial spin textures, such as magnetic skyrmions. Here we

Quasistatic Antiferromagnetism in the Quantum Wells of SmTiO 3 /SrTiO 3 Heterostructures

February 20, 2018
Author(s)
Ryan F. Need, Patrick B. Marshall, Eric Kenney, Andreas Suter, Thomas Prokscha, Zaher Salman, Brian Kirby, Susanne Stemmer, Michael J. Graf, Stephen D. Wilson
The magnetic properties of high-density SrTiO 3 quantum wells embedded within the antiferromagnetic Mott insulator SmTiO 3 are explored via muon spin relaxation and polarized neutron reflectometry measurements. The one electron per wel acquired by the

Ion-Gel-Gating-Induced Oxygen Vacancy Formation in Epitaxial La 0.5Sr d0.5^CoO^d3-d Films from in operando X-ray and Neutron Scattering

December 19, 2017
Author(s)
Jeff Walter, Guichuan Yu, Biqiong Yu, Alexander Grutter, Brian Kirby, Julie Borchers, Zhan Zhang, Hua Zhou, Turan Birol, Martin Greven, Chris Leighton
Ionic-liquid/gel-based transistors have emerged as an ideal means to accumulate high charge carrier densities at the surfaces of materials such as oxides, enabling control over electronic phase transitions. Substantial gaps remain in the understanding of

Compensated Ferrimagnetism in the Zero-Moment Heusler Alloy Mn 3 Al

June 30, 2017
Author(s)
Michelle Elizabeth Jamer, Yung Jui Wang, Gregory M. Stephen, Ian J. McDonald, Alexander J Grutter, George E. Sterbinsky, Dario A. Arena, Julie A. Borchers, Brian J Kirby, Laura H. Lewis, Bernardo Barbiellini, Arun Bansil, Don Heiman
While antiferromagnets have been proposed as components to limit stray magnetic fields in spintronics devices, their inability to be spin polarized inhibits their use. Compensated ferrimagnets are a unique solution to this dilemma since they have zero net

Magnetic Properties of Epitaxial CoCr Films with Depth-Dependent Exchange-Coupling Profiles

April 27, 2017
Author(s)
Lorenzo Fallarino, Brian Kirby, Matteo Pancaldi, Patricia Riego, Andrew L. Balk, Casey W. Miller, Paolo Vavassori, A. Berger
We present a study of the compositional and temperature dependent magnetic properties of epitaxial CoCr thin films whose composition has a bathtub-like depth profile Co/Co 1→1- x cCr 0→x c/Co 1-x cCr xc /Co 1-x c→1Cr x c→0^/Co with the highest Cr